Slightly enlarged bilateral hilar shadows refer to enlargement or thickening of the hilum bilaterally on chest imaging, chest X-ray, or chest CT, and are most often caused by inflammation, tuberculosis, tumors, or bronchiectasis, or enlarged lymph nodes. Because the hilum is mainly composed of airways, blood vessels and lymphatic vessels, it is the structure where these anatomical parts enter and exit. It is better to do further enhancement CT to clarify the diagnosis of the enlarged hilar shadow. The most common is inflammation, but it should not be ignored to exclude the possibility of tumor, especially for the history of smoking, chronic lung disease and elderly patients.